Problem w/ Matrox Millenium

[brians@Aureal.com (Brian Sassone)]

Hi,

I'm seeing a problem when using one of our PCI controllers in conjunction
with a Matrox Millenium graphics card.  It appears that the Matrox card is
retrying (for long periods of time) a mem-write (from the CPU) to its 
address space.  Our controller gets every other bus cycle and is trying to 
master a memory-read from system memory.  We are also getting continually
retried until we fail (meaning that our real time requirements simply aren't
met.)  We are seeing somewhere in excess of 256 retries.

I suspect that it is the Matrox card retrying our cycle, although I can't
prove this.  I can't think of a reason why the host bridge would be doing 
the retrying unless there is some strange side effect from the retries the 
Matrox card is issuing for its own cycles.  We have tested this on two
different Intel chipsets (HX and FX) and still see the problem.  I've also 
heard problem reports from modem users (overruns) when using the Matrox card
which seems to indicate the same problem.

Has anybody seen similar problems or problems with the Matrox card in
particular?  Is there any explicit requirements in the PCI spec the
prohibits a device from retrying cycles other than it's own?  

Thanks for any help!


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Brian Sassone (brians@aureal.com)                Aureal Semiconductor
Senior Design Engineer                           4245 Technology Drive
510-252-4225                                     Fremont, California 94538
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